Rat snakes are passive and prefer to avoid confrontation. If confronted by danger they will most likely freeze rather than strike. Rat snakes attempt to scare off predators by coiling their bodies and vibrating their tails in dead leaves to simulate a rattlesnake. If this noise is not enough of a deterrent they produce a foul-smelling musk that they release on a predator if they are caught.

In the wild, black rat snakes enjoy a variable diet that includes birds and small rodents. This prey is killed by constriction that cuts off the blood flow to its organs. The prey is then swallowed headfirst as the snake inches its teeth forward one jaw at a time.

Female black rat snakes lay between 12 and 20 eggs at a time about five weeks after mating. The eggs are hidden under leaves or in hollow logs until they hatch two to three months later. Females can produce two clutches of eggs in one year.